Research On Identification Of Low Frequency Decay Oscillation Of Power System

With the continuous development of the 5G era of the Internet and the expanding power grid environment,large-capacity units are also being put into operation.The application of fast excitation is gradually widespread,and the incidence of low-frequency oscillations has increased to a certain extent.The cause of low-frequency oscillations is due to the negative damping effect of the power system,which often occurs on weakly connected,long-distance,heavy-load transmission lines.It is more likely to occur under the conditions of fast and high-magnification excitation systems.Low frequency oscillation(Low Frequency Oscillation,LFO)is one of the important problems that threaten the safe and stable operation of the power grid.In parallel operation of the generator set in the power grid,if it is affected by the disturbance,there will be relative swing between the rotors.Once there is insufficient damping,it is easy There is continuous oscillation.The transmission power on the transmission line is also prone to oscillation.This paper first proposes an adaptive update method for low-frequency decay oscillations in power systems,and a robust algorithm for identifying the frequency,damping factor,and amplitude of exponentially damped sine wave(EDS)signals.Under the condition of no noise,the exponential convergence of the proposed identification method is proved by time scale change,variable transformation,slow integral manifold,averaging method and Lyapunov stability theorem.Under the condition of bounded additive noise,the anti-noise performance of each parameter identification was studied by using the perturbation system theorem and error synthesis principle.The boundary value of the identification error caused by high-frequency sinusoidal noise of frequency and damping factor can be adjusted by adjusting the design parameters.The simulation results prove the performance of the algorithm and verify the conclusion.Then,an experimental platform based on the algorithm proposed in this paper is built.The design of the hardware platform is mainly based on the FPGA platform,using DDS technology,using 51 single-chip AT89S51 as the main control,DAC conversion circuit,signal conditioning circuit composed of a signal generator module used to generate power system low frequency attenuation oscillation signal,and Design of signal analysis and processing module based on DSP28335.And give the corresponding software design.Finally,the results of the research and analysis in thispaper are summarized and analyzed,and the deficiencies in the algorithm are proposed,which points out the direction for the next research and analysis.